The Passive Car Cooler (PCC or Cool-A-Car) purpose is to prevent the car from heating up noticeably hotter than the ambient temperature of the outside air.
HOW IT WORKS
Cool-a-Car works by creating a partial vacuum inside the car cabin and causes air to circulate into the car cabin at a rate faster than it normally would if the Cool-a-Car is not fitted. The partial vacuum will be created by the effect of the sun’s heat heating up air inside a thermally absorbent chute (flue). As the volume of air compared with the surface area of the flue is greater than the cabin volume/cabin surface area the air will heat up significantly faster. As the hot air rises within the flue it will cause a negative pressure, relative to the pressure of the outside air and the pressure inside the cars cabin. Together with inlets for outside air, which is at ambient temperature, the action of the flue will cause outside air to be sucked into the car, thereby causing the air inside the cabin to remain closer to the ambient temperature outside the cabin.
By increasing the rate of flow of air inside the car's cabin - replacing it with outside air, the overall effect is a net cooling of the cars cabin - keeping it approximately equal to the outside temperature of air around (outside) the car.